Tamper resistant rugged keypad

ABSTRACT

A tamper-resistant or tamper-evident keypad device for use in secure transactions. The keypad comprises multiple security mechanisms to prevent tampering to the device, and thus access to users&#39; private information. The keypad is made of resilient materials and contains a tamper-resistant collar for housing the keypad&#39;s connector interface. The keypad comprises a multi-layered printed circuit board with at least two internal security-shield layers comprising switch trace protection, as well as additional security layers for tamper protection. The keypad comprises a silicon-rubber keypad actuator that engages tamper switches on the flexible security circuit. The keypad comprises metal discs mounted on the front or rear face of the flexible circuit and an optional dome layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 13/873,523, filed on Apr. 30, 2013, which claimsthe benefit of Provisional Patent Application Ser. No. 61/640,957, filedMay 1, 2012, each of which are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention relates to a rugged keypad capable of resistingtampering attempts. More specifically, it relates to a keypad capable ofresisting third parties' attempts to acquire signals associated with keystrokes on the keypad.

BACKGROUND OF THE INVENTION

Various devices require a user to enter data into a system using akeypad or other input device (hereinafter a “keypad”). The location ofthe keypad may subject it to various environments including adverseweather and the potential for tampering and/or vandalism.

The data being entered by a third party user may be sensitive, such as aPIN (personal identification number) or other personal or financialinformation. It is desirous that the keypad be resistant to bothtampering and vandalism. While vandalism is not condoned, the signs ofvandalism are generally recognized by the owner of the keypad or thethird party user of the keypad. In contrast, if a criminal is successfulin tampering, the owner or the third party user may not appreciate thatthe keypad has been tampered with and may use it, therein potentiallygranting the thief access to the third party user's information.Therefore, it is also desirable that the keypad be resistant totampering, and show visible signs if the device has been tampered.

SUMMARY OF THE INVENTION

It is recognized that there are certain points/locations within akeypad, which a criminal/thief may attempt to access. The keypad of thepresent invention has certain elements/features to reduce thepossibility that a thief can access these locations without necessarilyrendering the keypad un-useable, or at a minimum placing a user onnotice of the tampering.

One aspect of the present invention is a keypad for connecting to amachine having a connector interface, comprising a housing having afront panel with an outer face and inner surface, the front panel havinga plurality of openings and a plurality of sides projecting from thefront panel defining an area; a plurality of keycaps protruding throughthe openings on the front panel from the inner surface to the outerface; a multi-layer printed circuit board having a front face having aplurality of conductive pathways, wherein the movement of one of thekeycaps connects with one of the plurality of conductive pathways, themulti-layer printed circuit board having a back face with a plurality ofterminals associated with at least some of the conductive pathways; twoor more security-shield layers within the multi-layered printed circuitboard comprising switch trace protection interposed between the frontand back faces, comprising a pair of conductive pathways positionedaround the periphery of each layer creating a closed loop fordetermining if the multi-layered printed circuit board has been edgetampered with; a flexible security circuit interposed between the innersurface of the front panel of the housing and the multi-layer printedcircuit board, the flexible security circuit having a plurality ofconductive pathways spaced apart by about 0.08 mm to about 0.8 mm fordetermining if the flexible security circuit has been tampered with; aplurality of metal discs mounted to the top face of the flexiblesecurity circuit; a plurality of connectors extending from terminals onthe back face of the circuit board to the connector interface of themachine; and a collar for encircling the connectors that extends fromthe back face of the multi-layer printed circuit board to the machine tolimit unauthorized access to the plurality of connectors.

One embodiment of the keypad for connecting to a machine having aconnector interface is wherein the collar is made of hardened toolsteel.

One embodiment of the keypad for connecting to a machine having aconnector interface is wherein the housing comprises tamper-resistantmetal.

One embodiment of the keypad for connecting to a machine having aconnector interface further comprises a silicon-rubber keypad actuatorinterposed between the inner surface of the front panel of the housingand the flexible security circuit wherein the silicon-rubber keypadactuator engages tamper switches on the flexible security circuit.

One embodiment of the keypad for connecting to a machine having aconnector interface further comprises a dome layer interposed above theflexible security circuit. One embodiment of the keypad for connectingto a machine having a connector interface further comprises a dome layerinterposed below the flexible security circuit.

One embodiment of the keypad for connecting to a machine having aconnector interface is wherein the housing has an opening to accommodatea window lens for viewing a display carried by the machine.

One embodiment of the keypad for connecting to a machine having aconnector interface is wherein a plurality of the connectors comprises ablock with a front face and a back face, the block having a plurality ofalternating conductors and insulators extending parallel to each other,the block having an insulating layer encircling the plurality ofalternating conductors and insulators such that the block makes contactbetween the back face of the multi-layer printed circuit board and themachine via the front and back faces.

Another aspect of the present invention is a keypad for connecting to amachine having a connector interface, comprising a housing having afront panel with an outer face and inner surface, the front panel havinga plurality of openings and a plurality of sides projecting from thefront panel defining an area; a plurality of keycaps protruding throughthe openings on the front panel from the inner surface to the outerface; a multi-layer printed circuit board having a front face having aplurality of conductive pathways, wherein the movement of one of thekeycaps connects with one of the plurality of conductive pathways, themulti-layer printed circuit board having a back face with a plurality ofterminals associated with at least some of the conductive pathways; twoor more security-shield layers within the multi-layered printed circuitboard comprising switch trace protection interposed between the frontand back faces, comprising a pair of conductive pathways positionedaround the periphery of each layer creating a closed loop fordetermining if the multi-layered printed circuit board has been edgetampered with; a flexible security circuit interposed between the innersurface of the front panel of the housing and the multi-layer printedcircuit board, the flexible security circuit having a plurality ofconductive pathways spaced apart by about 0.08 mm to about 0.8 mm fordetermining if the flexible security circuit has been tampered with; aplurality of metal discs mounted to the top face of the flexiblesecurity circuit; a silicon-rubber keypad actuator interposed betweenthe inner surface of the front panel of the housing and the flexiblesecurity circuit wherein the silicon-rubber keypad actuator engagestamper switches on the flexible security circuit; a plurality ofconnectors extending from terminals on the back face of the circuitboard to the connector interface of the machine; a collar for encirclingthe connectors that extend from the back face of the multi-layer printedcircuit board to the machine to limit unauthorized access to theplurality of connectors; and a rear backer secured to the housing forenclosing the area.

One embodiment of a keypad for connecting to a machine having aconnector interface is wherein the collar is made of hardened toolsteel.

One embodiment of a keypad for connecting to a machine having aconnector interface is wherein the housing comprises tamper-resistantmetal.

One embodiment of a keypad for connecting to a machine having aconnector interface is wherein the housing has an opening to accommodatea window lens for viewing a display carried by the machine.

One embodiment of a keypad for connecting to a machine having aconnector interface is wherein a plurality of the connectors comprises ablock with a front face and a back face, the block having a plurality ofalternating conductors and insulators extending parallel to each other,the block having an insulating layer encircling the plurality ofalternating conductors and insulators such that the block makes contactbetween the back face of the multi-layer printed circuit board and themachine via the front and back faces.

One embodiment of the keypad for connecting to a machine having aconnector interface further comprises a dome layer interposed above theflexible security circuit. One embodiment of the keypad for connectingto a machine having a connector interface further comprises a dome layerinterposed below the flexible security circuit.

These aspects of the invention are not meant to be exclusive and otherfeatures, aspects, and advantages of the present invention will bereadily apparent to those of ordinary skill in the art when read inconjunction with the following description, appended claims, andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of theinvention will be apparent from the following description of particularembodiments of the invention, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe invention.

FIG. 1 shows a perspective view of one embodiment of the keypad of thepresent invention.

FIG. 2 shows a side exploded view of one embodiment of the keypad of thepresent invention.

FIG. 3 shows a front view of a multi-layer printed circuit board of oneembodiment of the keypad of the present invention.

FIG. 4 shows a perspective view of the keypad actuator of one embodimentof the keypad of the present invention.

FIG. 5A, FIG. 5B, and FIG. 5C show front and back views of a flexiblesecurity circuit of embodiments of the keypad of the present invention.

FIG. 6A and FIG. 6B show a back view and an inner layer of themulti-layer printed circuit board of one embodiment of the keypad of thepresent invention.

FIG. 7 shows a front view of the backer plate of one embodiment of thekeypad of the present invention.

FIG. 8A and FIG. 8B show perspective views of a holder of one embodimentof the keypad of the present invention.

FIG. 9 shows a perspective view of a connector of one embodiment of thekeypad of the present invention.

FIG. 10 shows a cross-sectional view of one embodiment of the keypad ofthe present invention.

FIG. 11A shows a front view of one embodiment of the keypad of thepresent invention with metal disks bonded to the flex circuit.

FIG. 11B shows a side view of one embodiment of the keypad of thepresent invention with metal disks bonded to the flex circuit.

FIG. 11C shows a perspective view of one embodiment of the keypad of thepresent invention with metal disks.

FIG. 12 shows tight line width spacing and metal discs of one embodimentof the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A keypad is used to enter data into a device or machine such as anautomatic teller machine (ATM), a credit card reader, or a point of sale(POS) or financial terminal. While the keypad may be used with othersecured devices such as a card reader for security reasons, it still isnot desirable to allow a third party to gain information regarding thekey strokes made to enter information such as a personal identificationnumber (PIN) or other personal or financial information. The keypad ofthe present invention has certain elements and features to prevent athird party from attempting to access information from within thekeypad.

The keypad of the present invention must meet a standard level ofsecurity. The testing is typically conducted by an independent testingagency. The testing agency connects the keypad to a machine and thenuses various means and methods to attempt to break into the keypad. Ifthey break in, or gain access to any information, the keypad fails, andif they cannot break in, the keypad device passes the security testing.One industry standard is the PCI Data Security Standard (“DSS”), andmore specifically the PIN Transaction Security (“PTS”) Requirements forManufacturers. These standards are technical and operationalrequirements set by the Payment Card Industry (“PCI”) Security StandardsCouncil, which is comprised of several major credit card companies. Thestandards globally govern all merchants and organizations that store,process, or transmit this data, and include specific requirements forsoftware developers and manufacturers of applications and devices usedin the transaction process. (See www.pcisecuritystandards.com). The newrequirements are Point of Interaction (POI) Modular SecurityRequirements v3.1, and are designed to, among other things, deter accessto user information for 8 hrs.

In FIG. 1, a perspective view of one embodiment of the keypad of thepresent invention is shown. More particularly. FIG. 1 shows aperspective view of a housing 22 of a keypad 20. The keypad 20 has ahousing 22 with a front panel 24. The front panel 24 has a plurality ofopenings 26 for receiving keycaps 28 (not shown). In addition, the frontpanel 24 of the housing 22 has an optional second opening 30 forreceiving a window lens 32. The window lens 32 allows a user to see ascreen located on a machine 16, which is shown in phantom. The machine16 is what the keypad 20 is secured to when installed. As will beexplained in further detail below, the signal generated by the keypad 20is used by the machine 16 to complete certain processes such as enteringthe PIN on an ATM machine, a credit card reader, or a point of sale(POS) or financial terminal.

Still referring to FIG. 1, the housing 22 of the keypad 20 has aplurality of sides which define an area, or box. The housing 22 has amounting edge 38 with a plurality of openings 40 for assisting insecuring and sealing the keypad 20 to the machine 16. A plurality offasteners 42 are shown exploded away from the housing 22.

In FIG. 2, a side exploded view of one embodiment of the keypad of thepresent invention is shown. More particularly, FIG. 2 shows a sideexploded view of the keypad 20 where a series of components 46 includingthe keycaps 28 and the window lens 32 are retained in the area, or boxdefined by the housing 22. The components 46 are held in the area, orbox, defined by the housing 22 using various alignment techniques and arear backer 48 that is secured to the housing 22 by a plurality offasteners 50. While a majority of the components of the keypad 20 willbe described in further detail, a brief description of all the majorcomponents 46 is described here. Interposed between the window lens 32and the front panel 24 of the housing 22 is a seal 52 that seals thewindow lens 32 in the opening 26 of the housing 22 (not shown). A lensbacker spacer 54 is interposed between the window lens 32 and the rearbacker 48. In certain embodiments, the keypad 20 has a silicon rubberkeypad actuator 56 interposed between the keycaps and a multi-layerprinted circuit board 58. The keypad 20, in addition, has a double-sidedflexible security circuit 60 interposed between the silicon rubberkeypad actuator 56 and the printed circuit board 58. Interposed betweenthe flexible security circuit 60 and the silicon rubber keypad actuator56 is a dome layer (not shown). In certain embodiments, the dome layercould is located in between the flexible security circuit 60 and theprinted circuit board 58. In certain embodiments the dome layer is ontop of the flexible security circuit. In certain embodiments, the domelayer is under the flexible security circuit. The dome layer (not shown)is comprised of a high-temperature polyester, metal, or the like.

Still referring to FIG. 2, interposed between the multi-layer printedcircuit board 58 (“PCB”) and the rear backer 48 is a PCB/backer spacer72. Another component 46 interposed between the multi-layer printedcircuit board 58 and the rear backer 48 is an insulator 74 that isinterposed between the PCB 58 and the PCB/backer spacer 72. A gasket 78overlies the housing 22 to prevent exposure to the elements, such asdust, moisture and the like. In certain embodiments, the keypad 20, inaddition, has a rear insulator 80 interposed between the rear backer 48and the machine 16. It is recognized that the side of the housing 22 insome portions extends into the machine 16.

As will be explained in further detail below, the back face of theprinted circuit board 58 has a plurality of contacts 102 (as best seenin FIG. 6A), from which the printed circuit board 58 conveys signals orinformation to the machine 16. The keypad 20 has a plurality ofconnectors 68, referred to as zebra connectors in one embodiment, toconvey this signal. One of the features of the keypad 20 of the presentinvention is preventing access to the flow of information through thezebra connectors 68. It is understood that zebra connectors are just oneform of connector. Other connectors known to those of skill in the artare also applicable, including pin connectors, and the like.

Preventing access to the flow of information is done, in part, by usinga hardened steel collar 70 which, in addition to positioning theconnectors 68, blocks access to the connectors. The collar 70 ispositioned between the rear backer 48 and the PCB/backer spacer 72, butsits on the same plane as the PCB/backer spacer 72 when assembled. Thus,the collar 70 blocks any attempt at side entry to the connectors 68 bywould-be thieves.

The keypad of the present invention contains multiple securitymechanisms to prevent tampering with the device and accessing users'private information. One security mechanism is provided by the collar70, which is made of hardened steel that has been machined in such a wayas to form a physical block against access to the connectors 68 withinthe keypad. In one embodiment, the tool steel comprises tool steel ofgrade A2. In another embodiment, the collar comprises tool steel ofgrade D2. In other embodiments other grades of tool steel known to thoseof skill in the art are used. In all embodiments, the tool steel ishardened to RC63, or better, based on the Rockwell C hardness scale.

Another level of security is provided by the double-sided flexiblesecurity circuit 60 (as best seen in FIGS. 5A, 5B and 5C). Thisdouble-sided flexible security circuit is designed such that allinformation is erased if the double-sided flexible security circuitsenses tampering, thus preventing any access to user data. Oneembodiment of the double-sided flexible security circuit comprisesmultiple layers produced via screen printing techniques using carbon,silver, and other conductive inks, and an ultraviolet dielectric layer.One embodiment of the double-sided flexible security circuit comprisesmultiple layers produced via etching copper layers from a polyamidesubstrate. Other methods known to those of skill in the art may be usedto produce the fine traces used in the embodiments of the presentinvention. The line widths for the traces of the present invention rangefrom about 0.08 mm to about 0.25 mm. The gap width between adjacenttraces of the present invention range from about 0.08 mm to about 0.20mm. In certain embodiments of the present invention, the line width andspacing for the center circuit loops is about 0.08 mm on 0.16centerlines.

Another security mechanism in one embodiment of the keypad of thepresent invention is the addition of metal discs to the top face of theflex circuit to provide a level of security on plastic housingassemblies that would be found on die-cast metal assemblies. See, FIGS.11A-11C. In certain embodiments, the discs are comprised of non-magneticmetal. In certain embodiments, the discs are comprised of stainlesssteel. In certain embodiments, the discs are comprised of 304 or 316stainless steel. In certain embodiments, the discs are about 3 mm indiameter. In certain embodiments, the discs are about 0.5 mmthicknesses. In certain embodiments of the discs, the discs are bondedto polyimide sing cyanoacrylate liquid adhesive followed by air curing.

Yet another security mechanism in one embodiment of the keypad of thepresent invention is a multi-layer printed circuit board with internalsecurity layers. In one embodiment of the present invention, themulti-layer printed circuit board has six layers. There are front andback layers, as well as multiple security-shield layers which sensepressure, drilling, disassembly, and the like. When tampering or damagecauses a break or discontinuity of electrical signal is sensed by asecurity-shield layer the electronically stored information is erased,thus preventing access to user data. The security-shield layers can bemulti-layered. There are generally two or more security-shield layers inthe PCB in order to provide access barriers to internal signal circuitlayers and additional built-in redundancy for heightened security.Lastly, the housing of the keypad can be made of a tamper-resistant ortamper-evident material such as metal. The vertical distance betweencopper layers is about 0.02 mm, thus preventing any drilling into theunit without detection.

In FIG. 3, a front view of a multi-layer printed circuit board of oneembodiment of the keypad of the present invention is shown. Moreparticularly, FIG. 3 shows a front view of the printed circuit board(PCB) 58 with a front face 82 that has a plurality of conductivepatterns 84 consisting of single or double pole switches, through whicha current may flow. In certain embodiments, the switches may be made outof gold-plated copper. In certain embodiments, the switches may becomprised of hard nickel. The pressing of a keycap 28, such as seen inFIG. 2, depresses a portion of the silicon-rubber keypad actuator andthe flexible security circuit such that carbon pills or carbon-coatedpads make contact on the back of the flexible security circuit whichtouches contacts on the PCB face to form a closed circuit with theassociated portion on the printed circuit board 58. As noted previously,there may also be a dome layer interposed between the silicon-rubberkeypad actuator and the flexible security circuit.

In FIG. 4, a perspective view of the keypad actuator 56 of oneembodiment of the keypad of the present invention is shown. Thesilicone-rubber keypad actuator 56 is interposed between the keycaps 28(as best seen in FIG. 2) and the PCB 58 to seal preventing weather, suchas rain, and contaminants such as dirt, from making contact with the PCB58. The silicone-rubber keypad actuator 56 would prevent water, dust,and other items which may enter through the openings 26 in the housing22 from making contact with any electrical component. Thesilicone-rubber keypad actuator 56 has a raised area 88 associated witheach keycap 28. The raised area 88 is flexible such that upon pushingthe keycap 28, the raised area 88 can collapse to apply pressure to thesilicone-rubber keypad actuator 56 overlying the proper location on theprinted circuit board 58. The resiliency of the raised area 88 allowsthe keycap 28 to move back into its resting position after a user stopsdepressing the keycap 28.

The keypad 20 may be located in locations outside of buildings andaccessible at all times of day and, therefore, potentially susceptibleto vandals and/or tampering. Components such as the housing 22 and thekeycaps 28 being made out of metal such as chrome-plated zinc reducessusceptibility to both vandals and tampering. While vandalism is notcondoned, if a third party took a sledge hammer to the keypad 20, theowner and most potential users would not attempt to enter sensitive datasuch as a PIN number in the keypad. However, a bigger concern istampering wherein a third party does something that is not readilyapparent when a user enters sensitive data such as a PIN number into thekeypad.

In FIGS. 5A, 5B, and 5C views of a flexible security circuit of anembodiment of the keypad of the present invention are shown. Moreparticularly, the flexible security circuit 60 has on the front or rearface a plurality of circuitry that is capable of detecting when a thirdparty attempts to drill through or otherwise penetrate the flexiblesecurity circuit 60. For example, if a third party attempts to drill ahole to access the printed circuit board by drilling a hole through theflexible security circuit 60, that hole through the flexible securitycircuit 60 would likely break the conductor pattern therein, changingthe flow of current through the front or rear face of the flexiblesecurity circuit. In certain embodiments, the front, or top, face of theflexible security circuit 60 has metal contacts that bridge betweencontacts on the printed circuit board when a keycap is depressed. Incertain embodiments, the rear face of the flexible security circuit 60has metal contacts that bridge between contacts on the printed circuitboard when a keycap is depressed.

Still referring to FIGS. 5A, 5B, and 5C, there are a variety of patternsavailable for the tamper sensing flexible security circuits. In oneembodiment, as shown in FIGS. 5A and 5B, the circuits are orientedperpendicular to each other. On a first surface is circuit A (as seen inFIG. 5A) and on the second surface is circuit B, which is orientedperpendicular to circuit A (as seen in FIG. 5B). In another embodiment,as seen in FIG. 5C, a complex pattern of circuits are on a single side.The traces vary in orientation and the width changes as the traces getcloser to the tamper circuit to PC board interconnect. The tampersensing properties of the flexible security circuit can be exercised ifcircuit A and circuit B touch, or if one of the circuits is cut. It isrecognized that the tight spacing of the traces enables very sensitivetamper detection. The tamper sensing properties of the flexible securitycircuit are also exercised in the separation of the tamper circuit to PCboard interconnect, which occurs with an attempt to disassemble. Asdisassembly is attempted, pressure applied by a compressive contact onthe SR keypad to the tamper circuit interconnect is reduced, causingseparation which also disturbs the security circuit. In one embodiment,the flexible security circuit also comprises a polyamide substrate withcopper on both the top and bottom surface, each with different etchpatterns. The flexible security circuit 60 further comprises a polyamidecap which is screen printed with carbon on the bottom surface to producea contact surface, a UV-cured dielectric spacer may be printed aroundthis contact to provide defection properties of the conductive contact.It is understood that other spacers are also possible, includingadhesive and dry film spacers, where the spacers are produced inadhesive form (wet) and dry film form.

In FIG. 6A, a back view of the printed circuit board of one embodimentof the keypad of the present invention is shown. More particularly, theback face 100 of the printed circuit board 58 is shown, where thecircuitry (conductive pattern 84) located on the front face of the PCB58 as seen in FIG. 3 is connected to a plurality of contacts 102 locatedon the back face 100 of the printed circuit board 58. It is the signalsand/or currents that are found at these contacts at the back of theprinted circuit board 58 that need to be conveyed to the machine 16.

In FIG. 6B, a security layer of the printed circuit board of oneembodiment of the keypad device of the present invention is shown. Thedual circuits A and B are located on the same surface, as in theflexible security circuit 60 shown in FIG. 5C. As seen in FIG. 6B, thecircuit pattern creates an inter-digitated pattern around the peripheryof the layer in addition to several spiraling patterns located atvarious locations. Just as with the flexible security circuits, it isrecognized that the tight spacing of the traces of the present inventionenables very sensitive tamper detection.

In FIG. 7, a front view of the backer plate 48 of one embodiment of thekeypad of the present invention is shown. Information is conveyed viathe connectors 68 (not shown) through an opening 106 in the rear backer48. The rear backer 48 is shaped to the housing such that the area, orbox, defined by the housing is sealed. The rear backer 48 has aplurality of holes for receiving fasteners S. The rear backer 48 hasseveral threaded posts T used for assembly of the keypad. The rearbacker 48 has a pair of openings 106 and 108. The larger opening 108 isaligned with the window lens located on the front panel of the housingsuch that a display located on the machine 16 can be seen (as best seenin FIG. 1). The smaller opening 106 is aligned with the connectors 102(as best seen in FIG. 6) located on the back of the printed circuitboard. While a detailed view of the PCB/backer spacer 72 as seen in FIG.2 is not shown, it likewise has an opening aligned with the connectors102 on the rear face 100 of the PCB 58.

In FIG. 8A and FIG. 8B perspective views of a collar of one embodimentof the keypad of the present invention are shown. The collar 70 has arectangular shape with a pair of channels 120 extending through thecollar 70. Other embodiments may have one or more such channels. In oneembodiment of the present invention, each channel 120 receives one ofthe zebra connectors 68. In addition, the collar 70 has a flange 122,wherein the flange 122 is sized to the opening in the PCB/backer spacer72 and the main body 124 is sized for the opening 106 in the rear backer48 or cover. The top 126 of the flange 122 of the collar 70 engages therear face 100 of the PCB 58 and the bottom 128 of the collar 70 engagesthe face of the machine 16. In a preferred embodiment, the collar 70 ismade of machined hardened tool steel such that a third party would havedifficulty accessing the zebra connectors by drilling through theholder, and at the same time not producing noticeable damage to thekeypad 20 that would be easily recognizable.

In FIG. 9, a perspective view of a connector of one embodiment of thekeypad of the present invention is shown. More particularly, aperspective view of a zebra connector 68 is shown where the zebraconnector 68 has a plurality of parallel spaced connectors 136 thatextend from the connection 102 on the rear face 100 of the PCB 58, asbest seen in FIG. 6, to the connectors 18 on the machine 16 (not shown).Other embodiments may be a single connection. Interposed between theconnectors 136 in the zebra connector 68 are internal insulators 138. Inaddition, there is an outside insulator 140 which encircles the entireset of connectors 136. Both the position of the connectors 68 and theitems that surround the connectors 68, such as the collar 70, create adeterrent to a criminal gaining access to the signal. It is understoodthat a variety of connectors can be used in embodiments of the presentinvention.

In FIG. 10, a cross-sectional view of one embodiment of the keypad ofthe present invention is shown. More particularly, the keypad 20 has ahousing 22 with a front panel 24. The front panel 24 has a plurality ofopenings 26 for receiving keycaps 28. The keypad 20 has a window lens 32covered by a seal 52 that seals the window lens 32 in the opening 26 ofthe housing 22. A lens backer spacer 54 is interposed between the windowlens 32 and the rear backer 48. The keypad 20 has a silicon rubberkeypad actuator 56 interposed between the keycaps 28 and a multi-layerprinted circuit board 58. The keypad 20, in addition, has a double-sidedflexible security circuit 60 interposed between the silicon rubberkeypad actuator 56 and the printed circuit board 58. In one embodiment,there is a dome layer interposed between the printed circuit board 58and the flexible security circuit 60 (not shown). The collar 70 ispositioned between the rear backer 48 and the PCB/backer spacer 72, butsits on the same plane as the PCB/backer spacer 72 when assembled. Thecollar 70 has one or more channels 120 extending through the collar 70.In addition, the collar 70 has a flange 122, wherein the flange 122 issized to the opening in the PCB/backer spacer 72 and the main body 124(not shown) is sized for the opening 106 in the rear backer 48. In oneembodiment, the top 126 of the flange 122 of the collar 70 engages therear face 100 of the PCB 58 and the bottom 128 of the collar 70 engagesthe face of the machine 16.

Referring to FIGS. 11A-11C, one embodiment of the keypad of the presentinvention comprising metal discs is shown. More particularly, FIG. 11Ashows a front view; FIG. 11B shows a side view; and FIG. 11C shows aperspective view. The purpose of the addition of metal discs to the faceof the flex circuit is to provide the same level of security on plastichousing assemblies as are found on die-cast metal assemblies. Morespecifically, in a plastic housing design, plastic material and rubberare used and the rubber actuator can be “nibbled” away with the intentof accessing the through hole in the circuit to apply solder to the padand thus close the detect circuit (make a permanent electrical loop). Inthe present invention, the addition of metal discs eliminates thatability to nibble away and reach the through hole, thus eliminating thispotential work-around the tamper contacts.

Referring to FIG. 12, tight line width spacing and metal discs of oneembodiment of the present invention is shown. In certain embodiments,the metal discs are bonded to the top face of the flexible circuit. Incertain embodiments, the metal discs are bonded by hand. In certainembodiments, the metal discs are bonded using SMT processes. In certainembodiments, the tolerances are ±0.1 mm. Much like the traces shown inFIG. 5C, a combination of fine traces are used external to the flexiblesecurity circuit for tamper prevention. The placement of the discscorresponds to the placement of the through holes in the layer, as bestseen in FIG. 5C.

The keypad of the present invention allows machine 16 to senseunpermitted entry into the keypad through various security mechanismswhich protect frontal, side, and rear attack on the keypad electronics.The frontal protection is accomplished with a double-sided flexiblesecurity circuit which senses tampering, including, but not limited todrilling activity into the switch cavity. This is also accomplished withthe addition of metal discs. There is also case separation protectioncomprised of tamper switches which sense a separation of the case; e.g.compression pads on the keypad/actuator which match to contact pads onthe back of the flexible security circuit, with further contact pads onthe multi-layer printed circuit board. There is also switch traceprotection of the multi-layer printed circuit board which has internalsecurity circuitry that encapsulates the switch circuits and protectsthose circuits from attack and detection. The side protection includes ahardened steel collar. This feature protects the Z-axis interconnectfrom the interface multi-layer printed circuit board to the clientelectronics multi-layer printed circuit board. This protects from sideattack into the keypad. The keypad of the present invention encompassesmany security mechanisms which together create a keypad that meets, orexceeds, the requirements of the PCI DSS Point of Interaction (POI)Modular Security Requirements v3.1, and as such deters access to auser's information for at least 8 hours.

While the principles of the invention have been described herein, it isto be understood by those skilled in the art that this description ismade only by way of example and not as a limitation as to the scope ofthe invention. Other embodiments are contemplated within the scope ofthe present invention in addition to the exemplary embodiments shown anddescribed herein. Modifications and substitutions by one of ordinaryskill in the art are considered to be within the scope of the presentinvention.

What is claimed is:
 1. A keypad for connecting to a machine having aconnector interface, comprising a housing having a front panel with anouter face and inner surface, the front panel having a plurality ofopenings and a plurality of sides projecting from the front paneldefining an area; a plurality of keycaps protruding through the openingson the front panel from the inner surface to the outer face; amulti-layer printed circuit board having a front face having a pluralityof conductive pathways, wherein a movement of one of the plurality ofkeycaps connects with one of the plurality of conductive pathways, themulti-layer printed circuit board having a back face with a plurality ofterminals associated with at least one of the plurality of conductivepathways; two or more security-shield layers within the multi-layeredprinted circuit board comprising switch trace protection interposedbetween the front and back faces, comprising a pair of conductivepathways positioned around a periphery of each layer creating a closedloop for determining if the multi-layered printed circuit board has beenedge tampered with; a flexible security circuit interposed between theinner surface of the front panel of the housing and the multi-layerprinted circuit board, the flexible security circuit having a pluralityof conductive pathways spaced apart by a distance of between 0.08 mm to0.8 mm for determining if the flexible security circuit has beentampered with; a plurality of metal discs mounted to a top face of theflexible security circuit; a plurality of connectors extending fromterminals on the back face of the circuit board to the connectorinterface of the machine; and a collar for encircling the connectorsthat extends from the back face of the multi-layer printed circuit boardto the machine to limit unauthorized access to the plurality ofconnectors.
 2. A keypad for connecting to a machine having a connectorinterface of claim 1, wherein the collar is made of hardened tool steel.3. A keypad for connecting to a machine having a connector interface ofclaim 1, wherein the housing comprises tamper-resistant metal.
 4. Akeypad for connecting to a machine having a connector interface of claim1, wherein the housing has an opening to accommodate a window lens forviewing a display carried by the machine.
 5. A keypad for connecting toa machine having a connector interface of claim 1, wherein the pluralityof the connectors comprises a block with a front face and a back face,the block having a plurality of alternating conductors and insulatorsextending parallel to each other, the block having an insulating layerencircling the plurality of alternating conductors and insulators suchthat the block makes contact between the back face of the multi-layerprinted circuit board and the machine via the front and back faces ofthe block.
 6. A keypad for connecting to a machine having a connectorinterface of claim 1, further comprising a silicon-rubber keypadactuator interposed between the inner surface of the front panel of thehousing and the flexible security circuit wherein the silicon-rubberkeypad actuator engages tamper switches on the flexible securitycircuit.
 7. A keypad for connecting to a machine having a connectorinterface of claim 6, further comprising a dome layer interposed abovethe flexible security circuit.
 8. A keypad for connecting to a machinehaving a connector interface of claim 6, further comprising a dome layerinterposed below the flexible security circuit.
 9. A keypad forconnecting to a machine having a connector interface, comprising ahousing having a front panel with an outer face and inner surface, thefront panel having a plurality of openings and a plurality of sidesprojecting from the front panel defining an area; a plurality of keycapsprotruding through the openings on the front panel from the innersurface to the outer face; a multi-layer printed circuit board having afront face having a plurality of conductive pathways, wherein a movementof one of the plurality of keycaps connects with one of the plurality ofconductive pathways, the multi-layer printed circuit board having a backface with a plurality of terminals associated with at least one of theplurality of conductive pathways; two or more security-shield layerswithin the multi-layered printed circuit board comprising switch traceprotection interposed between the front and back faces, comprising apair of conductive pathways positioned around a periphery of each layercreating a closed loop for determining if the multi-layered printedcircuit board has been edge tampered with; a flexible security circuitinterposed between the inner surface of the front panel of the housingand the multi-layer printed circuit board, the flexible security circuithaving a plurality of conductive pathways spaced apart by a distance ofbetween 0.08 mm to 0.8 mm for determining if the flexible securitycircuit has been tampered with; a plurality of metal discs mounted to atop face of the flexible security circuit; a silicon-rubber keypadactuator interposed between the inner surface of the front panel of thehousing and the flexible security circuit wherein the silicon-rubberkeypad actuator engages tamper switches on the flexible securitycircuit; a plurality of connectors extending from terminals on the backface of the circuit board to the connector interface of the machine; acollar for encircling the connectors that extends from the back face ofthe multi-layer printed circuit board to the machine to limitunauthorized access to the plurality of connectors; and a rear backersecured to the housing for enclosing the area.
 10. A keypad forconnecting to a machine having a connector interface of claim 9, whereinthe collar is made of hardened tool steel.
 11. A keypad for connectingto a machine having a connector interface of claim 9, wherein thehousing comprises tamper-resistant metal.
 12. A keypad for connecting toa machine having a connector interface of claim 9, wherein the housinghas an opening to accommodate a window lens for viewing a displaycarried by the machine.
 13. A keypad for connecting to a machine havinga connector interface of claim 9, wherein the plurality of theconnectors comprises a block with a front face and a back face, theblock having a plurality of alternating conductors and insulatorsextending parallel to each other, the block having an insulating layerencircling the plurality of alternating conductors and insulators suchthat the block makes contact between the back face of the multi-layerprinted circuit board and the machine via the front and back faces ofthe block.
 14. A keypad for connecting to a machine having a connectorinterface of claim 9, further comprising a dome layer interposed abovethe flexible security circuit.
 15. A keypad for connecting to a machinehaving a connector interface of claim 9, further comprising a dome layerinterposed below the flexible security circuit.